The present disclosure relates to digital manufacturing systems for building three-dimensional (3D) models. In particular, the present disclosure relates to deposition heads and head gantries for use with digital manufacturing systems, such as deposition-based digital manufacturing systems.
Digital manufacturing systems are used to build 3D models from digital representations of the 3D models (e.g., STL format files) using one or more layer-based additive techniques. Examples of commercially available layer-based additive techniques include fused deposition modeling, ink jetting, selective laser sintering, electron-beam melting, and stereolithographic processes. For each of these techniques, the digital representation of the 3D model is initially sliced into multiple horizontal layers. For each sliced layer, a build path is then generated, which provides instructions for the particular digital manufacturing system to form the given layer. For deposition-based systems (e.g., fused deposition modeling and ink jetting), the build path defines the pattern for depositing roads of modeling material from a moveable deposition head to form the given layer.
For example, in a fused deposition modeling system, modeling material is extruded from a moveable extrusion head, and is deposited as a sequence of roads on a platform in a horizontal x-y plane based on the build path. The extruded modeling material fuses to previously deposited modeling material, and solidifies upon a drop in temperature. The position of the extrusion head relative to the platform is then incremented along a vertical z-axis, and the process is then repeated to form a 3D model resembling the digital representation.
Movement of the underlying platform can require a substantial force load (e.g., up to several hundred pounds), particularly for platforms having large build areas. Such required loads are substantially greater than the forces that the deposition head is typically designed to withstand. Thus, if an error occurs while raising the underlying platform along the vertical z-axis, the platform may overshoot its intended position and potentially damage the deposition head. Accordingly, there is an ongoing need for mechanisms and techniques for reducing the risk of damage to deposition heads from contact with underlying platforms.